Abzu

Abzu is the true antagonist of the first season of Saint Seiya Omega. While pretending to serve Mars, Medea and Amor prey on Kouga to awaken his dark cosmo within and to summon Abzu, their true master.

Trivia: Abzu is an entity created for Saint Seiya Omega. He's sometimes mistaken by fans with Apsu, a Mesopotamian deity and an entity embodying fresh water.